From: Bartosz Golaszewski <redacted>


On Wed, 26 Jun 2024 13:29:21 +0800, Kent Gibson wrote:

The behaviour of request reconfiguration without a direction flag set is
ill-defined and badly behaved, for both uAPI v1 and v2.  I'll will refer
to such a configuration as 'directionless' here.  That refers to the
configuration requested, not the actual state of the line.

The configuration validation used during reconfiguration is borrowed from
the line request operation, where, to verify the intent of the user, the
direction must be set to in order to effect a change to the electrical
configuration of a line. But that validation does not allow for the
directionless case, making it possible to clear flags set previously
without specifying the line direction.

[...]

I applied the first two for fixes and will apply the remaining two for the
upcoming merge window once this gets upstream.

[1/4] gpiolib: cdev: Disallow reconfiguration without direction (uAPI v1)
      commit: 9919cce62f68e6ab68dc2a975b5dc670f8ca7d40
[2/4] gpiolib: cdev: Ignore reconfiguration without direction
      commit: b440396387418fe2feaacd41ca16080e7a8bc9ad

Best regards,
-- 
Bartosz Golaszewski [off-list ref]